1. Division of Endocrinology, Department of Medicine, Sungkyunkwan University School of Medicine, Seoul, Korea.
2. Division of Endocrinology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
3. Division of Endocrinology, Department of Internal Medicine, Graduate School of Medicine, Gachon University of Medicine and Science, Inchon, Korea.
4. Division of Endocrinology, Department of Internal Medicine, University of Ulsan College of Medicine, Seoul, Korea.
5. Division of Endocrinology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
6. Division of Endocrinology, Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea.